The utility model provides a distribution lines voltage monitoring devices and monitoring system, the device is including divider, control box and energy supply device, the control box is connected with divider and energy supply device respectively, the control box includes secondary divider, capture card and industrial computer, the capture card is connected with secondary divider and industrial computer respectively. The device not only can install in the position that has more lightning protection measure, can install moreover in the distribution lines position that does not have lightning protection measure or few lightning protection measure to monitor the net twine of joining in marriage of complete wave form change and pass by voltage signal, improve and join in marriage the degree of accuracy that the monitoring results of voltage was passed by to the net twine.